Method of making golf ball cores



July 15, 1941. P. KALOWSKI 2,249,612

METHOD OF MAKING GOLF BALL CORES Filed Nov. 12, 1938 Patented in, 15, 194i 2,249,612 METHOD MAKING GOLF BALL COBES Phillip Kalowski, Chicago, Ill., assignor, by mesne assignments, to Golf Ball, Inc., Chicago, 111.. a corporation of Illinois Application November 12, 1938, Serial No. 2 39,997

5 Claims. (Cl.154 18) This invention relates generally to the art of manufacturing golf balls containing a liquid or similar highly mobile core surrounded by resilient material, such as a tense rubber winding, and more particularly, to the method of forming the part known as the core on which the rubber winding is wound under tension.

It is well known in the art that a. highly mobile core combined with an envelope of rubber tape or thread wound under high tension gives a relatively long flying ball, and the higher the tension of the winding and the greater the mobility -of the core the longer will be the flight. Liquid cores have the greatest mobility, and for that reason a number of methods have been developed for enclosing this liquid in a flexible envelope of such nature that none will escape into the rubber windings and cause deterioration and loss of tension therein, and that the envelope itself shall be of uniform shape.

A few of the most common methods hereto fore used have been to. enclose the liquid in an oil-proof envelope of gelatin or the like, and then enclosing the gelatin envelope in a rubber envelope.

A still more recent method comprises the freezing of a spherical pellet of a core material composed of a mobile substance, and then enclosing said frozen pellet while frozen in a vulcanizable rubber envelope, then vulcanizing said envelope, again freezing'said mobile material, and while it is so frozen applying the winding thereto.

The last-mentioned method is probably the one.

facture as well as increased length of flight, unlformity and durability of the ball.

It is another object of this invention to provide a novel and improved method for the manufacture of the core for golf balls or the like, which ularly pointed out in the appended claims, it

being understood that various changes in the form, proportion, size and details of the apparatus .used with my new method, and various changes in the details of procedure of the method may be made without departing from the spirit or sacrificing any of the advantages of my inv'ention.

, For the purpose of facilitating an understanding of my invention, I have illustrated in the accompanying drawing apparatus which may be used in carrying out and practicing my invention from an inspection of which, when considered in connection with the following description,

will have added convenience in the manipulation of the core materials and at the same time decrease the cost of its manufacture.

With the foregoing and other objects in-view which will appear as the description proceeds, the

practice hereinafter fully described, and particmy invention, its mode of practice and many of its advantages should bereadily understood and appreciated.

Referring .to the drawing in which the samev characters of reference are employed to indicate corresponding or similar parts throughout the several figures of the drawing:

Figs. 1 to 5, inclusive, illustrate consecutive steps of my improved method in the manufacture of the improved core, as well as vertical sectional views of the apparatus employed;

Fig. 6 is a view in section and elevation of the core after the same have had the step shown in Fig. 5 completed thereon;

Fig. 7 is a sectional view of a vulcanizing mold with the core in section shown therein;

Fig. 8 is anelevational view of the completed core.

In general, my improved method consists of four steps, in the first of which a fiat sheet of raw rubber stock is placed over the cutting edge of a female member, and a male member is forced down into the female member drawing the raw rubber sheet into a substantially cup-shaped member with the edges of the sheet still protruding over the cutting edges of the female the use of these materials and may be employedv with any core material which is not stiff enough to hold its spherical shape in a ball winding machine or other golf ball forming apparatus.

-In the next step the cup-shaped member with the core material disposed therein is capped by invention consists of certain modes and steps of v placing a further sheet of raw rubber stock over the edges of the cup-shaped member and com binedly forcing the sheet to adhere to the edges thereof and cutting off the surplus to form a closed rubber envelope.

In the fourth and last step, the fllledenvelope thus formed is placed in a perfectly spherical mold and is vulcanized and cured to form the core shown in Fig. 8.

In the drawing in which Figs. 1 to 8 illustrate a preferred method of carrying out my process. the reference character I designates a sheet of raw rubber which is arranged in place over a female die member II, the said sheet resting upon the cutting edge I2 of said member ll.

7 The member I I is provided with an internal bore I3, the upper portion I4 of which is of slightly larger internal diameter, to form the ridge or flange I5 for a purpose to be hereinafter more fully described. The bottom of the bore I3 is of substantially conical formation, but it Obviously could be of any other convenient shape such, for example, as spherical. In the bottom wall of the member II is provided a central opening I. the purpose of which is to allow the escape of air from the bore I3 as the rubber sheet III is forced into the bore I3. The member II is adapted for disposition upon a suitable table or platform II having the raised projections It s as to keep the opening I6 free from obstruction.

A male member I9 of a diameter less than that of the inner diameter of the bore II by an amount to compensate for the desired thickness of the core envelope to be formed, is arranged for projection downwardly and into the female member II. The male member I8 is provided with a substantially hemi-spherical lower end. as shown in Figs. 1 and 2 of the drawing. The

projection of the male member I8 into the fespherical shape of the lower end of the male member I9.

der pressure upon the sheet 23, the result of which will be to pinch ofl between the die members II and 24 the overhanging lip portions of the sheet 23 and the shell 20, thereby forming a seam 28. In order to provide against a weakening of the wall of the finished core at the same or at the point where the shearing action takes place between the die members II and 24, I have prepared on the bottom face of the plate member 25 an annular depending ring portion E1, the outer diameter of which is substantially the same as that of the enlarged portion II of the bore I3 with the depth of said depending ring'portion being considerably less than the depth of said enlarged portion I4. The result of this arrangement will be to produce a relatively thickened portion or seam 28, as shown in Fig. 5, when the die member 24 has been brought down upon the die member II and caused'a cutting away of the excess rubber by its cooperation with the cutting edge I2.

The completel sealed shell 20 filled with the core material 22 is next removed from the die member II and will assume a shape substantially that as shown in Fig. 6, in which shape there will be noteda slight bulg g. of the top wall 21 indicating that the shell is completely filled with the core material and that the same is entirely free from any air other than that dissolved in the core material itself. The result of completely filling the shell with the core material will be to prevent any inertia forces to cause the ball within which the .core is subsequently placed to be untrue in flight due to slight shifting of the mass of liquid within its envelope.

The shell thus formed is-next placed in a suitable vulcanizing mold designated generally as an upper portion 28 and a lower portion 29, between which is provided a central cavity 30, the size and shape of which will be that of the desired finished core. The shell 20 being formed from When in this position it will be noted that the outer diameter of the shell will be substantially the same as the inner diameter of the bore ex cept, at the enlarged portion of the bore I4 directly above the inwardly extending flange Ii, at which point the diameter flares outwardly until at the cutting edge I2 it is substantially that of the cutting edge. Upon withdrawal of the male member I9 the shell 20 being made from raw rubber will retain its shape, which shape will be that substantially as shown in Fig. 3 of the drawing, and at which time the shell is ,com-. pletely filled with the core material-22, which material is composed of. a mobile substance such, for example, as the viscous liquids commonly employed. I

It will be understood that the present invention is not limited to the use of any specific core material, as the same may be employed with any core material which is not stiff enough to hold its spherical shape in a ball winding machine or other golf ball forming apparatus.

The next step in my improved process is to arrange a substantially fiat sheet of raw rubber stock 23 directly above and on top of the uppermOst edge of the shell 20, in which position said sheet 23 will contact and rest upon the protruding lips 2i of the shell 20 as shown more clearly in Fig. 4.

vulcanizable rawrubber, easily conforms to the shape of the cavity 30 and is molded during the vulcanizing and curing operation within the mold to a perfectly spherical shape. g

It will be noted that the resulting core will be perfectly free from any outer seams or protuberances which may'tend to cause the ball with which the core is used to be inaccurate. It will also be noted that the bead 26 has now been molded into the shelljof the core and forms an internal slightly thickened portion 3|, which is so slight as not to affect any of the propertiesof the spherical core.

The completed core is now ready for the capping orother covering operations, which operations may be performed by first freezing the nor- .mally liquid core material so as to give the core sufficient stiffness to hold its shape during the winding, capping or other covering operations. The freezing may be accomplished in any suitable and well-known manner by placing the same in a suitable freezing chamber and the temperature varied to the freezing point of the core material. Where the vulcanized rubber in the core envelope is not stiff enough to retain the cores in spherical form during the freezing of the core material suitable complete form members may be employed. 1

From the above it will be noted that by filling the core with the core material while in a normally liquid condition, as distinguished from first freezing the core material into a pellet. I am enabled to obtain a perfectly symmetrical core hav- ,ing an envelope of substantially uniform thick ness and one .that is completely filled with the core material and is absolutely free from any air bubbles or the like.

It will also be noted that my improved method has the added manufacturing advantage by dis pensing with' the necessity of first freezing the 'core material into pellets before capping the embodiment of the invention has been shown and described for illustrative purposes, the structural details are nevertheless capable of wide variation within the purview of my invention as defined in the appended claims.

I claim:

1. The method of making golf ball cores which comprises enclosing a normally mobile material in a cup-shaped member of vulcanizable rubber,

then capping said cup-shaped member with a sheet of vulcanizable rubber to completely seal the mobile material therein to the exclusion of any undissolved gases and then re-shaping said capped member to a perfect sphere in an appropriate vulcanizing and curing mold.

2. The method of making golf ball cores which comprises the formation of v a container of substantially cup shape of vulcanizable rubber having an open end, completely filling said container with a normally mobile material, covering said open end with a substantially fiat cap of vul-' canizable rubber and uniting the edges of said cap with the edges around the opening of said container, and then vulcanizing and curing the resulting sealed container in a spherical shaped mold, said container being void of undissolved gases therein by reason of said process.

3. The method of making golf ball cores which comprises the steps of placing a sheet of vulcanizable rubber over the opening of a female cylindrical member, forcing a round ended male stantially cup-shaped container having overhanging lip portions, filling said container to overflowing with a normally mobile liquid material, then piacing a substantially fiat sheet of similar vulcanizable rubber upon the overhanging lips of said filled container, thenforcing said sneet upon said container by means of a plate member which simultaneously unites the edges of said second-mentioned sheet and said overhanging lips or the container and trims off excess material, then removing the resulting container from said female member and then vulcanizing and curing the same in a spherical shaped mold.

4. The method of making a 'golf ball core which comprises filling a substantially cup-shaped member of vulcanizablematerial with suflicient normally mobile liquid material to completely fill said core in its completed'form to the exclusion of air, then capping said cup-shaped member with a sheet member of similar vulcanizable material, and then re-shaping the resulting member in an appropriate spherical vulcanizing and curing mold.

. .5. The method of making golf ball cores which comprises producing a substantially cup-shaped shell by placing a sheet of vulcanizable rubber over. the opening of a female substantially cylindrical member and forcing around-ended male member into said female member, the shell thus formed having over-hanging lip portions, completely filling said shell with a. normally mobile liquid material, then capping said shell to seal the said material therein by placing a substantially fiat sheet of vulcanizable rubber upon the over-hanging lip portions thereof and while the same is within the female member, and forcing said sheet upon said shell lip by bringing a plate member into the female member to form a sub- .PHILIIP KALOWSKI. 

